Process for coating and decoration of a substrate and printed article

Abstract

The present invention relates to a primer composition comprising water, keratin and a binder, and to a process for coating and decoration of a substrate comprising applying said primer to the substrate followed by one or more layers of a colored ink.

Description

[0001] PROCESS FOR COATING AND DECORATION OF A SUBSTRATE AND PRINTED ARTICLE

[0002] The present invention relates to a primer composition comprising water, keratin and a binder, and to a process for coating and decoration of a substrate comprising applying said primer to the substrate followed by one or more layers of a colored ink. Advantageously, the primed and printed substrate is suitable for use as a food packaging material.

[0003] BACKGROUND OF THE INVENTION

[0004] Packaging for fast moving consumer goods (FMCG) applications (such as food packaging) typically use synthetic plastic substrates such as biaxially oriented polypropylene (BOPP), polyethylene (PE), polyethylene terephthalate (PET), high density polyethylene (HDPE) or polyester, or cellulosic materials such as card, carton board, and card stock liners. Typically, pigment-based inks in either aqueous, solvent or radiation-curable matrices are used to decorate the substrates (e.g., plastics or card stocks) with images using a variety of different printing methods.

[0005] It is difficult to derive inks for the decoration of direct food contact packaging which are fully compliant with the various regulations of direct food contact. Furthermore, inks which are compliant are typically only capable of printing low resolution images by traditional printing methods such as screen printing. There is a requirement to be able to print high resolution images, especially by digital inkjet printing, using fully compliant direct food contact water-based inks in order to greatly improve the image quality for applications such as the interior of food packaging containers made from card stock, card and various plastics. The present invention addresses this requirement. In particular, the present inventors have discovered that the use of keratin in primers for food packaging applications imparts improved performance properties, such as adhesion, resistance, de-inkability, etc.

[0006] Keratin belongs to the family of fibrous structural proteins called scleroproteins. It is the most abundant structural protein found in hair, nails, feathers, horns, and claws of animals. Along with collagen, it is the most important biopolymer encountered in animals. Its characteristic feature is its high cysteine content as compared to other fibrous proteins like elastin, collagen and myofibrillar protein. Over the years, keratin has been extracted from chicken feathers, beaks, claws, nails, horns, hooves, hair and toenails. The other significant source of keratin is wool, which is the preferred source of keratin in the present invention, though other sources could also be selected to provide similar performance properties in primers.

[0007] Keratin particles have physical attributes allowing them to bind very well to certain water- soluble dyes, such as reactive, acid, FD&C and direct dyes. Plastic substrates such as BOPP, HDPE, PET and polyester-based packaging are not typically directly inkjet printable with such water-soluble dye-based inks due to drop spreading on the surface and very poor binding and fixation, as well as poor surface wetting. A primer preparation of keratin particles can be used to coat such plastics and cellulosic-based packaging materials which are compliant with the direct food contact regulations. The primed substrate may then be subsequently decorated with images using water-based dye inks containing food compliant soluble colorants to yield a decorated pattern with very good image quality and increased binding to the substrate.

[0008] The primers of the present invention are based on materials which are food packaging compliant and decorative inks can be used which are also food compliant (such as edible inks). The primers also contain materials which have a high bio-renewable carbon content (BRC). A further benefit is that dry heat fixation can be used, rather than energy-consuming steaming and washing or energy-intensive UV-curing. Typically, the primers and decorative inks are de-inkable after use to enable recycling of the substrate and potentially harvesting of the used keratin particles.

[0009] There are references which refer to various chemical pre-treatment methods for plastic or cellulosic packaging materials, for the subsequent decoration with pigment-based inks, but none describe the use of keratin particles as a material in a pre-treatment primer or the subsequent decoration of the primed substrates with water-soluble dye-based inks. Furthermore, there is no mention of the preparation of, for example, polyester, polyethylene, or polypropylene to be made receptive to water-based soluble dye inks. Additionally, there is no mention of the use of water-soluble dye inks to print images on plastic or cellulosic packaging materials which are completely direct food contact compliant. In the present invention, the inventors demonstrate how direct food contact compliant primers and edible inks can be used to solve these problems.

[0010] W020200026161 Al (Wool Research Organisation of New Zealand Incorporated) refers to compositions of pigments which are formed from keratin particles and dyes to be used in inks, paints and cosmetic formulations as colorant particles.

[0011] Citation or identification of any document in this application is not an admission that such represents prior art to the present invention.

[0012] DETAILED DESCRIPTION

[0013] In a first aspect, the present invention provides a process for coating and decoration of a substrate comprising; a. applying a primer coating to the substrate, the primer comprising water, binder and keratin; b. drying the primer by evaporation or heating; c. applying one or more layers of colored decorative ink over the top of the primer; and d. fixing the ink by evaporation or heating.

[0014] Preferably, the primer coating is applied directly to a surface of the substrate. As will be understood in the art, the primers are applied directly to the surface of the substrate where there is no intermediary layer between the substrate and the primer.

[0015] Preferably, the one or more layers of colored decorative inks are applied directly to the primed substrate. As will be understood in the art, the inks are applied directly to the primed substrate where there is no intermediary layer between the ink and the primed substrate. Preferably, the primers of the present invention are based on materials which are food packaging compliant and the decorative inks are also food compliant (such as edible inks). Preferably, the decorative inks are water-soluble dye-based edible inks.

[0016] The primers of the present invention incorporate keratin particles which can then be overprinted with water-soluble dye-based edible inks yielding so-called “lake” pigments in situ. As will be understood by the skilled person, a lake pigment is typically made by precipitating a water-soluble dye with an inert material, e.g., keratin. In one example, a primer coating comprising keratin particles, an edible binder comprising a gum or other edible polymer, and a carrier liquid, such as water, can be applied to the surface of a substrate and allowed to dry (either through evaporation of water or forced heating). The resulting coated substrate contains a matrix of keratin particles and edible binder, with the keratin being located towards the top surface and able to act as a binding site for the printing inks.

[0017] Typically, the keratin suitable for use in the present invention is prepared from keratin fibres derived from animal sources including animal hair, wool or fur (such as from sheep, goat, alpaca, cow, pig and the like); animal horns, nails, claws and hooves (such as from cattle, goats, antelope); and animal feathers and scales (such as from birds and fish). Preferably, the keratin particles are derived from wool, more preferably sheep wool.

[0018] The keratin particles suitable for use in the present invention may have an average particle size of from about 150 nm to about 50 pm. Preferably, the keratin particles have an average particle size of from about 1 pm to about 50 pm, more preferably from about 3 pm to about 25 pm, even more preferably from about 5 pm to about 15 pm.

[0019] Preferably, the primers of the present invention comprise from about 0.5wt% to about 12wt% keratin particles, preferably from about 0.5wt% to about 9wt% keratin particles. In some embodiments, the primers comprise from about 9wt% to about 12wt% keratin particles and the keratin particles preferably have an average particle size of less than about 10 pm, for example from about 150 nm to about 10 pm.

[0020] The primers of the present invention further comprise a binder. Typically, the binder used in the present invention is a food packaging compliant material and the primers are therefore suitable for direct and indirect food contact applications. Preferably, the binder is a food grade material, an edible material or a food grade and edible material. For example, the binder may be a food grade and edible material selected from the group consisting of gums, natural or synthetic polymers, natural or synthetic thickeners, pectins and mixtures thereof.

[0021] Suitable binders that may be used in the present invention include pectin (for example low methoxyl pectin), alginates, chitosan, inulin, pea proteins, natural rubbers, Guar gum, gellan gum, carob bean gum, gum Arabic, carrageenan, xanthan gum, starches (such as cornstarch, arrowroot powder, tapioca starch, potato starch), gelatin, agar-agar, celluloses (e.g., carboxymethylcellulose (CMC)), polysorbates, sorbitan monostearate, polyethylene glycol (PEG), glycerol, polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid co-polymers, styrene-maleic anhydride co-polymers, and mixtures thereof. Preferably, the binder is selected from polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid co-polymers, styrene-maleic anhydride co-polymers, natural gums, celluloses, pectin and mixtures thereof. More preferably, the binder is selected from polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid co-polymers, styrene-maleic anhydride co-polymers, Xanthan gum, Guar gum, celluloses, pectin and mixtures thereof.

[0022] Preferably, the binder is selected from polyacrylics, polyurethane dispersions (PUDs), pectin, Xanthan gum, Guar gum and mixtures thereof. More preferably, the binder is selected from pectin, Xanthan gum and Guar gum. As will be understood in the art, pectin, Xanthan gum and Guar gum are typically considered as plant-based polymers. Preferably, where the binder is pectin, it is low methoxyl pectin. In alternative preferred embodiments of the invention, the binder is selected from polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid co-polymers, styrene-maleic anhydride co-polymers, more preferably from polyacrylics and polyurethane dispersions (PUDs).

[0023] Preferably, the binder is a food-safe polymer for example a polymer selected from a polyacrylic, polyurethane dispersion (PUD), styrene-maleic acid co-polymer, styrenemaleic anhydride co-polymer, natural gum, cellulose, pectin and mixtures thereof.

[0024] Preferably, the primers of the present invention comprise from about 0.5wt% to about 40wt% of binder. In some instances, the binder may be present in from about 20 wt% to about 40wt%, for example, where the binder is a polyacrylic, polyurethane dispersion (PUD), styrene-maleic acid co-polymer or styrene-maleic anhydride co-polymer it may be present in from about 20wt% to about 40wt%. In alternative preferred embodiments, the binder may be present in from about 0.5 wt% to about 20wt% or more preferably from about 0.5wt% to about 10wt%. For example, where the binder is pectin, Xanthan gum or Guar gum it may be present in from about 0.5 wt% to about 20wt% or more preferably from about 0.5wt% to about 10wt%.

[0025] Preferably, the primers of the present invention comprise from about 0.5wt% to about 12wt% keratin particles; from about 0.5wt% to about 40wt% of binder; and from about 30wt% to about 70wt% water.

[0026] Preferably, the colored decorative ink comprises water and one or more dyes. More preferably, the colored decorative ink comprises water and one or more water-soluble dyes. Preferably, the dyes are selected from reactive, acid, FD&C, direct dyes and natural dyes, more preferably acid, FD&C and natural dyes.

[0027] In almost all cases, where reactive, acid, FD&C or direct water-based dye inks are printed onto plastic substrates or cellulosic packaging materials without primers, the resulting image quality is extremely poor and the inks exhibit either poor adhesion or a total lack of adhesion. As a result, once the food packaging substrate has been printed, there is a significant quantity of either hydrolysed or unreacted dye which is washed off during the subsequent processes and the printed images become illegible. Additionally, this leads to a large quantity of contaminated wastewater.

[0028] Preferably, the primers and method of the present invention are suitable for direct and indirect food contact applications on plastic substrates. Alternatively, the primers are not food compliant but may be used for applications where food compliance is not required.

[0029] The primer coated substrate (i.e., primed substrate) can subsequently be decorated using dye-based edible inks, preferably inkjet inks, and cured preferably using dry heat to afford complete fixation of the dyes to the substrate. Advantageously, the primed and printed images exhibit good image quality, good rub and water resistance, and the entire coating may be readily de-inked from the substrates utilising aqueous alkaline treatment for reuse or recycling of the substrate. Preferably, both the primer and edible inks are fully compliant with direct food contact (DFC) regulations, for example EU Framework Regulation EC 1935 / 2004 on materials and articles intended to come into contact with food; Swiss Ordinance on Materials and Articles in Contact with Food (SR 817.023.21) (revision February 2024); and US FDA CFR Title 21.

[0030] Coating of various substrates, for example films such as BOPP, HDPE, PE, polyester or polypropylene can be performed using these simple coating treatments. The keratin / binder / water primer coating according to the present invention can be deposited on the substrate by a wide variety of processes, for example slot coating, printing, spray coating, nozzle coating or any other suitable deposition method. The coating is then dried, preferably using dry heat or forced air convection to evaporate the water. Subsequently, one or more colored inks can be printed onto the primed surface using a wide variety of processes such as screen, gravure or preferably high-resolution inkjet printing. The colored inks are then fixed by drying, preferably using either forced air or dry heat methods to yield a decorated substrate. Preferably, the decorated substrate has improved properties compared to the use of non-keratin containing primers. Once the substrate has been primed with the primers of the invention containing keratin, a suitable set of water-based edible dye inks, such as reactive dye inks, acid dyes inks, or preferably FD&C dye edible inks or direct dye inks, can be printed onto the surface of the primed substrates and then dry heat or forced air convection used to fix the printed inks. It has been found that improved adhesion and resistance properties can be obtained using the primers and method of the invention, allowing the printing of substrate types which were not previously theoretically possible.

[0031] Preferably, the primers are colorless or opaque off-white. Preferably, the primers comprise a high content of bio-renewable carbon (BRC) content. BRC containing raw materials are those which are derived either totally or partially from plant-based feedstocks rather than fossil fuel feedstocks. A high level in a primer is typically at least >50%w / w (excluding the water content). Using keratin particles and plant-based polymers, which are both composed of BRC content can significantly increase the BRC of the applied primers. Preferably, the primers of the present invention are based on 100% BRC content. Preferably, the inks and primers can be fully removed (de-inked) after use by treatment of the substrate with aqueous base solutions, enabling the substrates to be recycled. The BRC content of all the primer compositions is provide in Table 17.

[0032] The first advantage of using the process of the present invention is that almost complete fixation can be achieved compared to printing the same water-based dye ink set onto conventionally prepared and pre-treated substrates. The environmental benefit is that the waste generated from subsequent processing of the packaging substrates is negligible, rather than being heavily contaminated with significant quantities of unreacted dyes.

[0033] A second advantage is that it completely inverts the current understanding of ink types which can be used to decorate certain substrates. Prior to this invention, there is no evidence of using water-based dye inks to decorate the surface of polyester, polyethylene, polypropylene, etc. A third advantage is that as a consequence of the improved fixation yield, the printed images have superior color strength (depth) and improved sharpness (less bleed) to those printed using classical and known methods.

[0034] A fourth advantage is that the printed substrates are found to exhibit superior print quality, rub fastness, water-resistance and scratch resistance compared to substrates prepared without primer.

[0035] A fifth advantage is that the printed images exhibit improved color fastness and light fastness with much improved image quality. It is well known that once an FD&C dye is “laked” to a carrier (in this case keratin), the lightfastness is significantly improved over the dyes alone.

[0036] The primers and decorative inks used in the present invention are both indirect and direct food contact compliant, for example in compliance with EU Framework Regulation EC 1935 / 2004; Swiss Ordinance; and US FDA CFR Title 21. Preferably, the primers are composed completely from food compliant ingredients, including direct food contact compliant keratin particles, to ensure that the primers are direct food contact compliant. An indication of which examples are Direct Food Contact Compliant (DFC) and which are Indirect Food Contact Compliant (IFC) is provided in Table 18.

[0037] Preferably, the primer layer and decorative ink layer, whilst stable to water in the pH range of 6-9, can be readily de-inked by relatively mild alkaline solutions. More preferably, the primer layer and decorative ink layer, whilst stable to water in the pH range of 6-9, can be readily de-inked by relatively mild alkaline solutions such as sodium hydroxide 2% aqueous solution. More preferably, the primer layer and decorative ink layer, whilst stable to water in the pH range of 6-9, can be readily de-inked by sodium hydroxide 2% aqueous solution.

[0038] In some embodiments, it is preferable to limit the level of yellowing in the primers as many printers prefer the appearance imparted by a non-yellowing primer. However, in an alternative embodiment, the primers can be formulated (for example with certain grades of pectin) to result in a yellower finish to provide accentuated color contrast when colored inks are printed over the primer.

[0039] The primers used in the present invention can be prepared by simply mixing, for example, an edible gum prepared in water (such as a Guar gum, pectin, gellan gum, carob bean gum (i.e., a galactomannan vegetable gum extracted from the seeds of the carob tree), gum Arabic, carrageenan, cellulose gum, xanthan gum etc.); with milled keratin particles, optionally with the addition of a preservative such as a polysorbate 20, polysorbate 40, polysorbate 80, polysorbate 60, citric acid, acetic acid and sorbic acid. Optionally, a polymer, preferably a food-safe polymer could be used in addition to or instead of the gum or pectin.

[0040] The keratin particles are typically milled to obtain the requisite particle size. Milling can be performed using a suitable bead milling machine such as an Eiger laboratory bead mill (from Eiger Torrance Ltd.) equipped with a suitable grinding media. Suitable grinding media include 0.8mm Ytterbium-Zirconium Oxide grinding media. Preferably, milling is performed for up to 60 minutes, more preferably for up to 45 minutes, more preferably for up to 30 minutes, more preferably for up to 20 minutes. As used herein, “up to” includes the endpoint such that “up to” 60 minutes (for example) includes 60 minutes.

[0041] Optionally, and advantageously for plastics, a wetting agent which is direct food contact compliant, such as mono-, di-, and tri-glycerides of fatty acids, lecithin, cholesterol, alkyl glycosides and phytosterols may be incorporated in the primers of the invention. Alternatively, food safe keratin particles could be added to a commercially available edible primer to provide a keratin- containing food safe primer. These primers may contain a mixture of natural gums and / or binders. Simple mixing is sufficient to provide a primer which can then be applied to a plastic substrate such as biaxially oriented polypropylene (BOPP), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET) using a variety of application methods including, but not limited to screen printing, offset printing, flexographic printing, screen printing, inkjet printing, spray coating, dip coating, draw down coating or slot coating. The coatings are preferably dried by using forced air convection, thermal methods such as heating or radiative methods such as NIR. Preferably, the primer coatings are dried at room temperature (20-22°C) or by heating at 60°C in a standard convection oven.

[0042] The substrates that are suitable for use in the present invention typically include plastic substrates and cellulosic substrates. Preferably, the substrate is a plastic substrate selected from biaxially oriented polypropylene (BOPP), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET) and polyester. Alternatively, the substrate is preferably a cellulosic substrate selected from paper, card stock and carton board.

[0043] Preferably, the primed substrates are subsequently printed with inkjet inks in which the colorants are drawn from the series of water-soluble reactive dyes, acid dyes, basic dyes, FD&C dyes, natural dyes or any other water-soluble dyes. Either simple inks where a dye is dissolved in water can be applied, or more complex inks which are formulated for deposition by techniques such as inkjet printing can be applied. In the case of the inkjet printing inks, there are edible inkjet inks which are fully food compliant such as the SensiJet FSE inks (Sun Chemical) and Tapestry inks (Sun Chemical). Images can be printed on the primed substrates, preferably using digital inkjet deposition methods, although other methods of printing can be utilized. Finally, the decorated substrates are dried again, preferably in-line, to evaporate the carrier liquids from the inks using forced air convection, thermal methods such as heating or radiative methods such as NIR.

[0044] Preferably, the inks are dried at from about 20°C to 90 °C.

[0045] Suitable FD&C dyes that can be used in the present invention may include FD&C Blue Nos. 1 and 2, FD&C Green No. 3, FD&C Red Nos. 3 and 40, FD&C Yellow Nos. 5 and 6, Orange B, Citrus Red No. 2, annatto extract, beta- carotene, grape skin extract, cochineal extract or carmine, paprika oleoresin, caramel color, fruit and vegetable juices, and saffron. Additional dyes that are suitable for use in the present invention include beets (i.e., beetroot-derived colorants), purple potato-based colorants, purple / red cabbage-base colorants, and the synthetic dye carmine.

[0046] The primers of the present invention may further optionally comprise one or more water- miscible co-solvents. Typically, the water-miscible solvent is suitable for food packaging applications. Water-miscible solvents that are suitable for food packaging applications may include glycerol, monopropylene glycol, ethylene glycol, diethylene glycol, 3-methoxy-3- methyl-1 -butanol (MMB), propylene glycol monomethyl ether (PM), dipropylene glycol monomethyl ether (DPM), and combinations thereof. Accordingly, the primers of the present invention may optionally further comprise glycerol, monopropylene glycol, ethylene glycol, diethylene glycol, 3 -methoxy-3 -methyl- 1 -butanol (MMB), propylene glycol monomethyl ether (PM), dipropylene glycol monomethyl ether (DPM), and combinations thereof. Preferably, where used, the water-miscible co-solvent is selected from glycerol, monopropylene glycol, ethylene glycol, diethylene glycol and combinations thereof, more preferably from glycerol and monopropylene glycol.

[0047] Preferably, once the substrate has performed its function, the primer and decorative inks can be removed (de- inked) by soaking in mildly alkaline caustic soda solution.

[0048] Definitions

[0049] Unless stated otherwise, as used herein, an FD&C dye is an FDA certified colour additive. These additives are approved for use in foods, drugs and cosmetics under the FDA’s Food, Drug, and Cosmetic Act (FD&C Act).

[0050] Unless stated otherwise, as used herein, a natural colorant (or dye) is a substance derived from natural sources, such as plants, animals, or minerals, used to impart color to food, cosmetics, textiles, and other products. These colorants are typically extracted from fruits, vegetables, spices, flowers, and other natural materials. Unless stated otherwise, as used herein, an acid dye is a dye that can anionically bind to a fiber and a direct dye is a dye that can adhere to a fiber by non-ionic forces.

[0051] Unless stated otherwise, as used herein, edible (e.g., an edible ink, primer or binder) means any item that is safe for humans to eat, i.e., any item that can be consumed and digested by a consumer and that does not cause adverse effects to the health of said consumer.

[0052] Unless stated otherwise, as used herein, pectin is a naturally occurring substance (polysaccharide) found in fruits, including berries, apples and citrus fruits. Pectin typically has a weight average molecular weight of 50,000 to 180,000 Da.

[0053] Unless stated otherwise, as used herein, LM pectin is low methoxyl pectin, i.e., pectin that has a level of esterification of less than 50%, such that less than 50% of the acid groups on the polysaccharide rings are esterified. Typically, LM pectin is thermally reversible.

[0054] Unless stated otherwise, as used herein, card stock is a paper having a weight of about 275 gsm.

[0055] As will be understood in the art, the term “de-ink” or “de-inking” means removal of an ink from a printed substrate.

[0056] Unless stated otherwise, the terms "particle size" or "average particle size" used herein refer to the volume distributed median particle diameter (equivalent spherical diameter corresponding to 50% of the volume of all the particles, read on the cumulative distribution curve relating volume % to the diameter of the particles - often referred to as the "D(v,0.5)" value or Dv50). Unless stated otherwise, particle size is suitably measured by dynamic light scattering (DLS). Preferably, particle size is suitably measured by dynamic light scattering (DLS) using a Malvern Zetasizer. Unless stated otherwise, particle size is suitably measured by DLS in deionized water at 20 °C. Unless stated otherwise, the BRC content is determined in accordance with ASTMD6866- Method B (AMS) using NIST Standard Reference Material (SRM) 104990C. In all cases, water is excepted from the BRC content.

[0057] As used herein, the terms "molecular weight" or "average molecular weight" is a reference to the weight average molecular weight (Mw). Unless stated otherwise, the molecular weight is suitably measured by gel permeation chromatography by comparison with a polystyrene standard. For instance, molecular weight determination may be conducted on a Hewlett-Packard 1050 Series HPLC system equipped with two GPC Ultrastyragel columns, 103 and 104 A ( 5 pm mixed, 300 mm x 19 mm, Waters Millipore Corporation, Milford, MA, USA) and THF as mobile phase. The flow rate in the columns is 1.0 ml / min, column temperature is 40°C, a differential refractive index detector (RI) and a UV-detector (254nm) were used. The skilled person will appreciate that this definition of molecular weight applies to polymeric materials which typically have a molecular weight distribution.

[0058] The present invention is further illustrated by the following set of numbered paragraphs and combinations of numbered paragraphs resulting from the dependencies and back- references as indicated. In particular, it is noted that in each instance where a range of numbered paragraphs is mentioned, for example in the context of a term such as "The method of any one of paragraphs 1 to 5", every numbered paragraph in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to " The method of any one of paragraphs 1, 2, 3, 4 and 5". Further, it is explicitly noted that the following set of numbered paragraphs is not the set of claims determining the extent of protection, but represents a suitably structured part of the description directed to general and specific aspects of the present invention.

[0059] 1. A process for the coating and decoration of a substrate comprising; a. applying a primer coating to the substrate, the primer comprising water, binder and keratin; b. drying the primer by evaporation or heating; c. applying one or more layers of colored decorative ink over the top of the primer; and d. fixing the ink by evaporation or heating.

[0060] 2. The process of paragraph 1 , wherein the resulting printed construct is a food packaging material.

[0061] 3. The process of paragraph 1 or 2, wherein the ink in step c is edible.

[0062] 4. The process of any preceding paragraph, wherein the ink in step c is applied by inkjet printing.

[0063] 5. The process of any preceding paragraph, wherein the keratin is derived from sheep’s wool.

[0064] 6. The process of any preceding paragraph, wherein the substrate is selected from the group consisting of polymeric materials and cellulosic materials.

[0065] 7. The process of paragraph 6, wherein the cellulosic material is paper or carton board.

[0066] 8. The process of any preceding paragraph, wherein the primer comprises 0.5-12% keratin.

[0067] 9. The process of any preceding paragraph, wherein the binder is selected from the group consisting of polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid copolymers, styrene-maleic anhydride co-polymers, natural gums, celluloses, pectin and mixtures thereof.

[0068] 10. The process of any preceding paragraph, wherein the primer and inks are suitable for DFC applications.

[0069] 11. The process of any preceding paragraph, wherein the primer and inks are suitable for IFC applications.

[0070] 12. The process of any preceding paragraph, wherein the binder is a food grade and edible material selected from the group consisting of gums, natural or synthetic polymers, natural or synthetic thickeners and pectins.

[0071] 13. The process of any preceding paragraph, wherein the primer is based on 100% BRC.

[0072] 14. The process of any preceding paragraph, wherein the primer and decorative layers are de-inkable.

[0073] 15. The process of any preceding paragraph, wherein the primer further comprises water- miscible co-solvents. 16. The process of any preceding paragraph, wherein the primer further comprises one or more surfactants and / or preservatives.

[0074] 17. A printed article resulting from the process of any one or more of paragraphs 1-16.

[0075] The present invention has been described in detail, including various embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of the present disclosure, may make modifications and / or improvements on this invention that fall within the scope and spirit of the invention.

[0076] EXAMPLES

[0077] The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended, nor should they be interpreted to, limit the scope of the invention.

[0078] Materials

[0079] HDPE was sourced from Supply Services and is described as PES200 10VN sheets.

[0080] Food wrap film refers to TimTam wrappers, Grade 7, multilayer film.

[0081] Card stock refers to 275gsm A4 sheets supplied by Supply Services.

[0082] Keratin WSP powder refers to food compliant keratin particles with a D50 particle size of d50 13.5pm supplied by Wool Source, New Zealand.

[0083] Keratin IW 15 powder refers to food compliant keratin particles with a D50 particle size of d50 9.2pm supplied by Wool Source, New Zealand.

[0084] FD&C Blue 1 ink was supplied by Over The Top, and was composed of water, propylene glycol, FD&C Blue 1 dye, sodium benzoate and citric acid.

[0085] Comparative Example 1 : DFC / Edible Primer without Keratin (100% BRC*1

[0086] The primer was prepared by adding Citrem '' (a citric acid ester of mono- and diglycerides from Danisco) 0.02g to 95.09g of deionized water, followed by Imwitor 742’’' (a blend of mono-, di-, and triglycerides, mainly of caprylic and capric acid from IOI Oleochemical) 0.15g, and the resulting mixture stirred at room temperature using a high speed mechanical stirrer for 30 minutes. Next, sorbitol (Modernist Pantry) 1.00g was added and stirred for a further 5 minutes. Low methoxyl pectin (Modernist Pantry) 3.55g was then added and mixing continued for 2 hours. 50% citric acid solution in water 0.193g, was then added to adjust the pH to 3.7. The pH was measured at 3.7 using a standard pH probe, the surface tension was measured at 26.48dynes using a Kibron Aqua Pi surface tensiometer.

[0087] *BRC refers to carbon-containing materials derived from animal, plant, fruit or vegetable bases ^Edible materials

[0088] Inventive Example 2: DFC / Edible Primer with 1% WSP keratin (100% BRC)

[0089] Primer samples were prepared by mixing l%w / w of WSP keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates.

[0090] An aliquot of Examples 1 & 2 was applied to card stock, HDPE and typical plastic food wrapper materials (as defined above). The aliquot was applied to the substrates using a metal Shandon gradient spreader (used in thin layer chromatography) resulting in a wet film thickness of 200pm. The substrates were dried at both room temperature (20-22°C) and 60°C in a standard convection oven before applying a rubber stamped image of an edible ink containing FD&C blue 1 dye. The substrates were then allowed to dry at 20- 25°C (room temperature) for a period of 2 minutes. Subsequently, dry rub fastness, wet (water) rub fastness and wet (ethanol) rub fastness tests were performed. De-inking with a solution of 2%w / w sodium hydroxide in water was then performed at room temperature and the de-inking efficacy assessed. This protocol was used for all of the subsequent examples.

[0091] Inventive Example 3: DFC / Edible Primer with 5% WSP keratin (100% BRC)

[0092] Primer samples were prepared by mixing 5%w / w of WSP keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates. Primed and printed substrates were prepared for testing as above. Inventive Example 4: DFC / Edible Primer with 10% WSP keratin (100% BRC)

[0093] Primer samples were prepared by mixing 10%w / w of WSP keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates. Primed and printed substrates were prepared for testing as above.

[0094] Inventive Example 5: DFC / Edible Primer with 1% IW15 keratin (100% BRC)

[0095] Primer samples were prepared by mixing l%w / w of IW15 keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates. Primed and printed substrates were prepared for testing as above.

[0096] Inventive Example 6: DFC / Edible Primer with 5% IW15 keratin (100% BRC)

[0097] Primer samples were prepared by mixing 5%w / w of IW15 keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates. Primed and printed substrates were prepared for testing as above.

[0098] Inventive Example 7: DFC / Edible Primer with 10% IW15 keratin (100% BRC)

[0099] Primer samples were prepared by mixing 10%w / w of IW15 keratin particles into the Comparative Example 1 edible primer base. The mixture was mixed for 30 seconds using an Ultraturrax T25 mixer at 13,500rpm at room temperature. The resulting primer is suitable for application to various substrates. Primed and printed substrates were prepared for testing as above.

[0100] Table 1: Dry Rub Fastness Results1- Card Stock Dry rub fastness was measured using a dry cotton swab which was manually wiped across the stamped image. The rub fastness was assessed by assigning a rating between 1-5, where 1 (worst) was assigned for 1-5 dry rubs before the image was distorted; 2 was assigned for 6-15 dry rubs; 3 was assigned for 16-25 dry rubs; 4 was assigned for 26-50 dry rubs; and 5 (best) was assigned for over 50 dry rubs. X = dry rub fastness at room temperature; and A = dry rub fastness at 60°C. This protocol was used for all rub test, with the possible exception of whether the cotton swab was dry or wet.

[0101] Notes to Table 1:

[0102] 'Dry and wet rub tests were not performed on non-primed substrates as the inks exhibited very poor adhesion, smearing and complete failure.

[0103] 2Film was not robust and failed even a low pressure rub fastness. This demonstrates that a primer with a 10% keratin loading using the larger particle size distribution WSP (d50 13.5um) does not provide sufficient wetting and uniform applied film coverage in some of the exemplified substrates. Though not wishing to be bound by theory, this is likely due to the higher particle size not being optimized for the different surface energies of the various substrates. For example card stock, with a typical surface energy of 50-55mN / m, is easier to wet than HDPE, which typically has a much lower surface energy of about 36mN / m, making surface wetting or printing much more difficult. The wetting is made even more complex as no wetting agent was used in Example 4 and the loading of 10% WSP keratin particles prevented the free flow of the applied primer to the substrate surface. Despite these characteristics, when Example 4 is applied to card stock, the water component soaks into the card stock and there is insufficient binder to physically bind the keratin particles to the surface of the card stock. When the keratin particles are smaller (i.e. Example 7), the smaller keratin particles are easier to coat with the binder on the surface of the card stock.

[0104] 3Example 7 has the same % loading of keratin particles as Example 4, but the particle size in Example 7 is significantly smaller. Though not wishing to be bound by theory, it is believed that the increased surface area in Example 7 imparts more robust film forming across the various substrates.

[0105] The data in Table 1 indicates that the Inventive and Comparative Examples performed equally well in terms of dry rub fastness on card stock at both room temp, and 60°C. The exception, as previously discussed, is Inventive Example 4, which is not suitable for this substrate.

[0106] Table 2: Dry Rub Fastness Results - HDPE (same testing protocol as Table 1)

[0107] 4When Example 4 is applied to HDPE, the substrate is impermeable, providing more opportunity for the binder to coat the keratin particles when applied to the surface of the HDPE compared to card stock. This shows that Example 4 is an Inventive Example but not preferred for HDPE.

[0108] The data in Table 2 indicates that Inventive Examples 2, 5 & 6 performed equally well in terms of dry rub fastness on HDPE vs. Comparative Example 1. Inventive Example 4 rub fastness is not as good as the other examples and thus less preferred for HDPE. Inventive Example 7 has equal rub fastness to the other examples at 60°C, but not as good at room temp.

[0109] Table 3: Dry Rub Fastness Results - Food Wrapper Plastic (same testing protocol as Table

[0110] 2Film was not robust and failed even a low pressure rub fastness

[0111] The data in Table 3 indicates that Inventive Examples 3, 5 & 6 performed better in terms of dry rub fastness on food wrapper plastic at room temp. vs. Comparative Example 1. Inventive Examples 2, 5 & 6 performed comparably to Comparative Example 1 At 60°C. Inventive Example 4 & 7 are not suitable for food wrapper plastic but are suitable for use on other substrates. Table 4: Wet (Water) Rub Fastness Results - Card Stock (same testing protocol as above. except cotton swap is wet, having been soaked in water)

[0112] 2Film was not robust and failed even a low pressure rub fastness.

[0113] The data in Table 4 indicates that Inventive Examples 2, 3, 5, 6 & 7 performed equally to Comparative Ex 1 for wet (water) rub fastness on card stock at room temp, and 60°C.

[0114] Inventive Example 4 is not suitable for use on card stock but is suitable for use on other substrates.

[0115] Table 5: Wet (Water) Rub Fastness Results - HDPE (same testing protocol as in Table 4) The data in Table 5 indicates that all Inventive Examples performed equally for wet (water) rub fastness on HDPE as Comparative Example 1 at both room temp, and 60°C.

[0116] Table 6: Wet (Water) Rub Fastness Results - Food Wrapper Plastic (same testing protocol as in Table 4) 2Film was not robust and failed even a low pressure rub fastness.

[0117] The data in Table 5 indicates that Inventive Examples 2, 5 & 6 performed equally well for wet (water) rub fastness on food wrapper plastic at room temp, and 60°C vs. Comparative Example 1. Inventive Examples 4 & 7 are not suitable for use on food wrapper plastic but are suitable for use on other substrates.

[0118] Table 7: Wet (Ethanol) Rub Fastness Results - Card Stock (same testing protocol as in

[0119] Table 4 except using ethanol instead of water to soak the cotton swab)

[0120] 2Film was not robust and failed even a low pressure rub fastness.

[0121] The data in Table 7 indicates that Inventive Examples 2, 3, 5 & 6 ink performed equally well for wet (ethanol) rub fastness on HDPE at room temperature and 60°C vs. Comparative Example 1. Surprisingly, Inventive Example 7 exhibited improved rub fastness at room temperature. Inventive Example 4 is not suitable for use on card stock but is suitable for use on other substrates.

[0122] Table 8: Wet (Ethanol) Rub Fastness Results - HDPE (same testing protocol as Table 7)

[0123] The data in Table 7 indicates that Inventive Examples 3, 5, 6 & 7 performed equally for wet (ethanol) rub fastness on HDPE at room temp, and 60°C vs. Comparative Example 1. Surprisingly, Inventive Example 4 exhibited improved rub fastness at room temp, and Inventive Example 2 exhibited improved rub fastness at 60°C.

[0124] Table 9: Wet (Ethanol) Rub Fastness Results - Food Wrapper Plastic (same testing as in Table 7)

[0125] 2Film was not robust and failed even a low pressure rub fastness.

[0126] The data in Table 9 indicates that Inventive Examples 3, 5 & 6 performed equally for wet (ethanol) rub fastness on food wrapper plastic at room temperature and 60°C vs. Comparative Example 1.

[0127] Note that the rub resistance properties for the examples shown in Tables 4-9 represent a marked improvement compared to non-primed prints, which exhibit no binding ability to the various substrates and thus were unsuitable for testing resistance properties.

[0128] Table 10: De-inking Results - HDPE - Primer Dried at Room Temp,

[0129] De-inking was assessed by visual inspection of the substrate and the condition of the printed ink and primer layer after each of the following process steps: i) soaking in deionised water for 60 seconds; ii) rinsing with tap water at room temperature; iii) submerging the printed in a 2%w / w sodium hydroxide solution in de-ionised water for 60 seconds at room temperature; iv) rinsing the substrate with cold tap water; v) performing a simple single rub test with a dry swab; vi) submerging the substrate in a 2%w / w sodium hydroxide solution in de-ionised water for 60 seconds at room temperature; vii) rinsing the substrate with cold tap water; viii) performing a simple single rub test with a dry swab. A score of 1 (worst) was awarded for no discernible difference in the image; 2 was awarded for a slight amount of deterioration in the printed ink layer; 3 was awarded for a significant visual removal in the reduction of the printed image color accompanied by a coloration of the sodium hydroxide solution; 4 was awarded for all the ink removed and noticeable removal of the primer; and 5 (best) was awarded for complete removal of the printed colored ink and the primer layer to afford a neutral substrate coloration.

[0130] This demonstrates that Inventive Examples 2 & 5 can be readily de-inked and perform either equal to or better than Comparative Example 1 on HDPE. Table 11 : De-inking Results - Food Wrapper Plastic - Primer Dried at Room Temp, (same testing protocol as in Table 10)

[0131] This demonstrates that Inventive Examples 2 & 5 can be readily de-inked and perform either equal to or better than Comparative Example 1 on food wrapper plastic.

[0132] Table 12: De-inking Results - HDPE - Primer Dried at 60°C (same testing protocol as in

[0133] Table 10)

[0134] This demonstrates that Inventive Examples 2, 5 & 6 can be readily de-inked and perform either equal to or better than Comparative Example 1 on HDPE.

[0135] Table 13: De-inking Results - Food Wrapper Plastic - Primer Dried at 60°C (same testing protocol as in Table 10)

[0136] This demonstrates that Inventive Examples 2 & 5 can be readily de-inked and perform either equal to or better than Comparative Example 1 on food wrapper plastic.

[0137] The next series of Examples 8-12 are for primers that may be suitable for direct food applications (depending on the local regulations), but could also be useful for indirect food contact, or non-food applications where water-based dye inks are printed over the top of primers, especially on plastic substrates. As in the prior examples, the addition of keratin enhances the properties of the primers. Table 18 contains the full list of DFC or IFC status for the examples.

[0138] Comparative Example 8: No primer (Solution of blue food dye) (0% BRC) An ink solution prepared from 10g of FD&C Blue 1 food dye dissolved to 100ml with deionized water was prepared and a single drop deposited onto HDPE substrate with a pipette. Adjacent to the ink drop, an image was rubber stamped.

[0139] Due to the lack of a primer, the ink exhibited no binding ability to the HDPE. Due to the obvious failure, no further resistance testing was performed.

[0140] Comparative Example 9: Acrylic dispersion primer without keratin (0% BRC)

[0141] Primer samples of Joncryl 8050E (BASF) were applied to sheets of HDPE using a Shandon gradient spreader (used in thin layer chromatography) resulting in a wet film thickness of 200pm. The sheets were cured at 120°C for 15 minutes. An ink solution prepared from 10g of FD&C Blue 1 food dye dissolved to 100ml with deionized water was prepared and a single drop deposited onto HDPE substrate with a pipette. Adjacent to the ink drop, an image was rubber stamped dropped on to the substrate and an image printed using pad printing. The substrate was oven dried for 20 minutes at 85°C, allowed to dry further overnight at room temp, then subjected to rub-fastness, water-resistance, alcohol rubresistance testing. On completion of the testing, the substrate was soaked in a 2% solution of sodium hydroxide in water for 2 minutes and the substrate inspected visually. A further soak in 2% sodium hydroxide solution in water for Ihr then yielded the final substrate for visual inspection.

[0142] Comparative Example 10: Polyurethane dispersion primer without keratin (0% BRC) Primer samples of Daotan DPU2261Z (Allnex) were applied to HDPE sheets and further prepared using the same process as Comparative Example 9.

[0143] Inventive Example 11: Acrylic Dispersion with 10% WSP keratin (43% BRC)

[0144] A primer solution was prepared by mixing 30g of commercially available resin Joncryl 8050 E (BASF) with 10g WSP keratin particles and 60g water. The primers were applied to HDPE sheets and further prepared using the same process as Comparative Example 9. The BRC content of this primer was calculated to be 43% as a portion of the carbon- containing raw materials are derived from animal (keratin), plant, fruit or vegetable bases. Inventive Example 12: Polyurethane dispersion with 10% WSP keratin (25% BRC)

[0145] A primer solution was prepared by mixing 30g of resin Daotan DPU2261Z (Allnex) with 10g WSP keratin particles and 60g water. The primers were applied to HDPE sheets and further prepared using the same process as Comparative Example 9. The BRC content of this primer was calculated to be 58% as a portion of the carbon-containing raw materials are derived from animal (keratin), plant, fruit or vegetable bases.

[0146] Table 14, Substrate Yellowing and Printed Image Quality

[0147] Substrate yellowing was observed for the Examples 8-12. A score of 1 was assigned where there was no discernable yellowing: a score of 2-4 was assigned for those samples which had intermediate yellowing; and a score of 5 was assigned where there was significant visible yellowing. In all cases, white HDPE was used as the substrate. Printed image quality was assessed for sharpness and color intensity by visual inspection. The sharpness was assigned a score of 5 (best) where there was no discernable bleed and 1 (worst) where there was detectable bleed. Color density was assessed based on a score of 1 (worst) for a pale image after curing and 5 (best) for a full strength image. A score of 2-4 was assigned for those samples which had intermediate color density.

[0148] The data in Table 14 demonstrates that primers made from polyurethane and acrylic dispersions with keratin added exhibit similar image sharpness and improved color intensity than those without keratin. Inventive Example 12 would be more suitable for applications where some degree of yellowing is desired to provide color contrast. Table 14 also shows that when polyurethane and acrylic dispersions are used as the binder, image sharpness is improved.

[0149] Table 15. Dry, Wet (water) and Wet (ethanol) rub fastness results

[0150] Dry and wet rub was assessed using the same protocol as Tables 1-9. Table 15 demonstrates that primers made from polyurethane and acrylic dispersions with keratin added exhibit improved dry rub resistance and similar wet rub resistance as primers without keratin.

[0151] Table 16, De-inking of Examples 8-12 was assessed by visual inspection of the substrate after soaking in 2% sodium hydroxide solution in water for 2 mins at 25°C, followed by rinsing the substrate with cold water. A score of 1 (worst) was awarded for no discernible difference in the image; 2 was awarded for a slight amount of wicking or spreading of the colored ink on the substrate; 3 was awarded for a noticeable by eye difference in the reduction of the printed image color accompanied by a coloration of the sodium hydroxide solution; 4 was awarded for at least 50% of the color being removed and 5 (best) was awarded for complete removal of the printed colored ink and the primer layer to afford a neutral substrate coloration. Further de-inking was measured by visual inspection of the substrate after soaking in 2% sodium hydroxide solution in water for a further 58 minutes (total of 60 minutes) at 25°C, followed by rinsing with cold water.

[0152] Table 16 shows that the ink primer examples containing keratin exhibit improved de-inking properties vs. those without keratin.

[0153] The next set of examples utilize gums instead of polymers, the advantage being that gums are typically 100% BRC materials. The Inventive Examples containing keratin perform better than the Comparative Examples without keratin.

[0154] Comparative Example 13: Xanthan Gum, no added keratin (100% BRC)

[0155] A primer solution was prepared by mixing 3.0g of xanthan gum (food grade) with deionised water (297g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. Primer samples were applied to sheets of card stock using a Shandon gradient spreader (used in thin layer chromatography) resulting in a wet film thickness of 200 um. The sheets were allowed to either air dry for 10 minutes or cured at 60°C for 2 minutes. An ink solution was prepared from 10g of FD&C Blue 1 food dye dissolved in 90g of deionized water and a single drop was deposited onto the card stock with a pipette. Adjacent to the ink drop, an image was rubber stamped onto the card stock.

[0156] Inventive Example 14: Xanthan Gum primer with 10% WSP keratin (100% BRC)

[0157] A primer solution was prepared by mixing 3.0g of xanthan gum (food grade) with deionised water (267g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of WSP keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0158] Inventive Example 15: Xanthan Gum primer with 10% IW15 keratin (100% BRC)

[0159] A primer solution was prepared by mixing 3.0g of xanthan gum (food grade) with deionised water (267g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of IW15 keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0160] Comparative Example 16: Guar Gum, no added keratin (100% BRC)

[0161] A primer solution was prepared by mixing 3.0g of xanthan gum (food grade) with deionised water (297g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. Primer and ink samples were applied to sheets of card stock using the same protocol as Example 13.

[0162] Inventive Example 17: Guar Gum primer with 10% WSP keratin powder (100% BRC) A primer solution was prepared by mixing 3.0g of Guar gum (food grade) with deionised water (267g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of WSP keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0163] Inventive Example 18: Guar Gum primer with 10% IW15 keratin (100% BRC)

[0164] A primer solution was prepared by mixing 3.0g of Guar gum (food grade) with deionised water (267g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of IW15 keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0165] In Examples 19-21 , pectin (another 100% BRC material) was used as the binder. Examples 19-21 are all suitable for DFC.

[0166] Comparative Example 19: Pectin Primer, no added keratin (100% BRC)

[0167] A primer solution was prepared by mixing 15.0g of pectin (food grade) with deionised water (285g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. Primer and ink samples were applied to sheets of card stock using the same protocol as Example 13.

[0168] Inventive Example 20: Pectin primer with 10% WSP keratin (100% BRC)

[0169] A primer solution was prepared by mixing 15.0g of pectin (food grade) with deionised water (255g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of WSP keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0170] Inventive Example 21: Pectin primer with 10% IW15 keratin (100% BRC)

[0171] A primer solution was prepared by mixing 15.0g of pectin (food grade) with deionised water (255g) and the resulting mixture stirred at room temperature using a magnetic stirrer for 10 minutes at room temperature. A sample of IW15 keratin particles 30.0g was added and the resulting mixture stirred for a further 30 minutes. Primer and ink samples were applied to sheets of plastic food packaging using the same protocol as Example 13.

[0172] Table 15, Dry Rub Fastness. Wet Water Rub Fastness. Wet Ethanol Rub Fastness In all cases, the Inventive Examples demonstrated comparable or improved dry and wet rub fastness vs Comparative Examples. Inventive Examples 14, 15, 17, 20 & 21 show that when pectin or gum is used as the binder, the primers with 10% keratin exhibit satisfactory film forming properties across the various substrates. Table 16, Yellowing of Card Stock Coated with Primers

[0173] The primers were applied to card stock as described previously. Visual inspection was performed and a score of 1 was assigned for no discernible yellowing of the card stock by eye, and a score of 5 was assigned for significant yellowing. As previously described, yellowing is advantageous for certain applications where color contrast is desired. Both comparative and inventive examples containing Guar gum and xanthan gum showed no discernible yellowing of the card stock once applied, while the examples containing pectin exhibited significant yellowing.

[0174] Table 17, Bio renewable Carbon Content (BRC) of all Examples

[0175] Table 18. DFC and Indirect Food Contact (IFC) Status of all Examples

[0176] *May be DFC compliant depending on the specific regulation.

Claims

CLAIMS1. A process for coating and decoration of a substrate comprising: a. applying a primer coating to the substrate, the primer comprising water, binder and keratin; b. drying the primer by evaporation or heating; c. applying one or more layers of colored decorative ink over the top of the primer; and d. fixing the ink by evaporation or heating.

2. The process of claim 1, wherein the primed and printed substrate is a food packaging material.

3. The process of claim 1 or 2, wherein the ink in step c is edible, preferably wherein the ink is a water-based edible ink.

4. The process of any preceding claim, wherein the ink in step c is applied by inkjet printing.

5. The process of any preceding claim, wherein the keratin is derived from sheep’s wool.

6. The process of any preceding claim, wherein the substrate is selected from the group consisting of polymeric materials and cellulosic materials.

7. The process of claim 6, wherein the substrate is a polymeric material selected from biaxially oriented polypropylene (BOPP), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET) and polyester-based materials.

8. The process of claim 6, wherein the substrate is a cellulosic material selected from paper, card stock or carton board.

9. The process of any preceding claim, wherein the primer comprises 0.5-12% keratin.

10. The process of any preceding claim wherein the binder is:(i) an edible gum, preferably selected from Guar gum, pectin, gellan gum, carob bean gum, gum Arabic, carrageenan, cellulose gum and xanthan gum; or(ii) selected from the group consisting of polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid co-polymers, styrene-maleic anhydride co-polymers.

11. The process of any of claims 1 to 9, wherein the binder is selected from the group consisting of polyacrylics, polyurethane dispersions (PUDs), styrene-maleic acid copolymers, styrene-maleic anhydride co-polymers, natural gums, celluloses, pectin and mixtures thereof.

12. The process of any preceding claim, wherein the primer and inks are suitable for direct food contact (DFC) applications.

13. The process of any of claims 1 to 11, wherein the primer and inks are suitable for indirect food contact (IFC) applications.

14. The process of any of claims 1 to 9, 12 or 13, wherein the binder is a food grade and edible material selected from the group consisting of gums, natural or synthetic polymers, natural or synthetic thickeners and pectins.

15. The process of any preceding claim, wherein the primer further comprises a wetting agent, preferably selected from the group consisting of mono-, di-, and tri-glycerides of fatty acids, lecithin, cholesterol, alkyl glycosides and phytosterols.

16. The process of any preceding claim, wherein the primer is based on 100% BRC content.

17. The process of any preceding claim, wherein the primer and decorative layers are de- inkable.

18. The process of any preceding claim, wherein the primer further comprises water- miscible co-solvents.

19. The process of any preceding claim, wherein the primer further comprises one or more surfactants and / or preservatives.

20. The process of claim 19, wherein the primer comprise a preservative selected from polysorbate 20, polysorbate 40, polysorbate 80, polysorbate 60, citric acid, acetic acid, sorbic acid and combinations thereof.

21. A printed article resulting from the process of any one or more of claims 1-20.

22. The printed article of claim 21 that is a food packaging material.

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